The invention relates to a method for simultaneously (1) cooling select surfaces of a hypersonic vehicle and (2) providing fuel as an energy source for consumption by a ramjet engine or the like in hypersonic vehicles.
At present, efforts have been undertaken to develop hypersonic vehicles capable of launching and reaching cruising speeds of several Mach.
Such hypersonic vehicles are, of course, subject to extreme temperature fluctuations within the vehicle's envelope of performance. Specifically, the leading edges of such vehicle frames as well as the internal construction associated with engines necessary to power the vehicle require that design parameters incorporate means for insuring structural survivability during hostile operating parameters.
Furthermore, consideration must be given to not only thermal environment requirements concerning the internal engine(s) but also to the fuel of choice which must realize a high heat of combustion while maintaining good cooling characteristics.
It is, therefore, an object of the present invention to provide a means for efficient structural cooling not only of the vehicle but also of the propulsion elements attendant thereto.
According to the invention, this object is achieved by means of an arrangement, whereby the fuel system is designed to allow the flow of fuel via fuel system conduits such that the fuel is caused to pass adjacent to areas of high thermal flux in hypersonic vehicle operation. Examples of such vehicle design and function are set forth in U.S. Pat. Nos. 4.919,364 (Apr. 24, 1990) and 4.934,632 (Jun. 19, 1990), both incorporated herein by reference.
Naturally, the propulsion system provides means known to those skilled in the art for conveying the fuel which has been heated by association with high temperature areas of the vehicle structure and directing such heated fuel to the combustion chamber of the vehicle engine.
In furtherance of the objective of the present invention, a select hydrocarbon fuel is utilized such that heat input to the fuel is used to thermally crack the fuel, cooling the structure through the endothermic pyrolysis reaction and forming reactive olefinic fuel fractions which are then injected into the high velocity internal flow stream of the vehicle propulsion system.